大亚湾三门岛珊瑚礁海域锥形宽水蚤(Temora turbinata)现场食物组成的分子生物学检测

Detecting in situ Copepod(Temora turbinata)diet in Sanmen Island,Daya Bay

浮游桡足类是连接海洋初级生产者和较高营养级生物的关键类群,了解其食物组成是理解海洋生态系统中物质与能量流通途径的基础。本文通过分子生物学手段研究大亚湾三门岛海域桡足类优势种锥形宽水蚤(Temora turbinata)现场食物组成,共检测出6种食物类群(住囊虫、甲藻、绿藻、有孔虫类、棘皮类、苔藓类),住囊虫是主要被摄食的生物类群(45.94%),其次是青绿藻纲(Prasinophyceae)的微微型真核自养生物(29.73%),另外还检测出2种锥形宽水蚤可能摄食的赤潮甲藻种类(Takayama acrotrocha和Karlodinium veneficum)。研究结果揭示了在食物限制环境下锥形宽水蚤灵活的摄食策略,突出了浮游动物在摄食传递过程及生态系统中的关键地位,将有助于解释浮游动物摄食行为在维持近岸生态系统平衡与稳定性中的作用。

Marine planktonic copepods are important predators in the coastal food webs,connecting the primary producers withupper trophic levels.Accurate determination of copepods' food composition is the basis of understanding the nutrient circulation and energy flow of marine ecosystems.We used molecular method to investigate the diet of the dominant copepod species Temora turbinatain the coastal area Sanmen Island,Daya Bay,China.The results of 18s rDNA clone libraries showed 6 feeding groups including Tunicata,Dinoflagellate,Green algae,Rhizaria,Echinodermata and Streptophyta.Surprisingly,Tunicata which was the dominant phytoplankton feeding gelatinous zooplankton in the food web consisting of a considerable proportion (45.94%)of the clones sequenced.The following feeding group wasautotrophic picophytoeukaryotes Prasinophyceae (Green algal).We also identified onecommon species ofbloom dinoflagellate in Temora turbinatabut had never been tested in copepod diet before.The results suggest that Temora turbinata has flexible feeding strategywhen phytoplankton biomassis restricted,consolidating the core status of planktonic animal in feeding transmission process,finally contributing to describe the complexity and stability of coastal ecosystems structure.